subtitle
n.
also sub-title, 1825, "subordinate or additional title, usually explanatory," in reference to literary works, from sub- "under" + title, n.. Applied to motion pictures by 1908. As a verb from 1858. Related: Subtitled.
〔李〕[sub-=subordinate副的；title n.标题 →] n.a subordinate title of a book or article副标题，小标题